testing afm per tsrm

[WillWorkFoBoost]

I dont know if this is the right place to post this but in multiple quests to find a good afm over the last couple years Ive gotten quite a few that were supposed to be good, but end up being bad. the sellers say they checked by the tsrm check, but for some reason the online tsrm only has the intake temp (Tha-E2) test..... My tsrm book has this page: http://www.supra.co.nz/87tsrm/EFI/efi98.htm It seems to me that maybe this should be a sticky somewhere if the tsrm online that everyones looking at doesnt have the correct info??? I just searched on google for the link but Ive always tested an afm by those resistances out of the book but no one I seem to talk to has any clue that theres anything other than Tha-E2 test.....

 

[jetjock]

The 87 TSRM has that test. Dunno about later ones. The key to doing it is (since you're measuring junctions) to remember polarity. That's what the arrows mean. It's still not a great method though. Much better is on the car (or off it ) using frequency.

My car left me with its original Karman sensor. Never used the spare I kept in a ziplock bag although it too tested OK using a vacuum cleaner when I sold it...

 

[WillWorkFoBoost]

The 87 one does but the tsrm that everyone ususally finds on here doesnt have that. Ive never had a bad one that didnt fail those resistance tests. even if its supposed to have 10-15kohms and its got 16 kohms it ususally dies with in a month or so. Ive probably gone through around 8 afms in 3 years. My point is, an afm is kinda a hot item, and the tsrm that alot of people are using only has intake temp test. should there be a sticky concering how to check it correctly, with resistance tests as well as frequency tests? Im tired of buying ones that are junk and then posting the correct way of checking them to the person who assured me it was good.

 

[jetjock]

Yeah, there's several things left out of the later books. Shame Toyota decided to do that.

The resistance test is good but nothing beats actually seeing the thing output a correct signal.

People seem to have lots of problems with the AFM. Even those who know better than to clean it. I dunno what to say except (iirc) 75% of the "bad" ones I tested over the years turned out to be good. I was even able to revive a few that'd been improperly cleaned. The rest were junk.

 

[JStoked]

So jj the only way i know to clean one safe is with compressed air that's in a can.( the same stuff you use to blow out a computer) Anyway i am on the right track to doing this?

 

[jetjock]

Actually you're somewhat on the right track although I'd be careful about pressuring it too much.

I used to vapor clean them with Freon TF. They can often be cleaned with refrigerant but you risk busting them. In your case turn the can upside down...most dusters are filled with R-134a. None of this is going to help if the optics/mirror have been solvent crazed though.

Btw if you're too cheap to buy real 134 you can also use the dusters to fill an AC system. Seriously. Leave it to the gum'mint to over regulate something and then permit millions of cans to be dumped into the air each year. It boggles the mind...